<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title>example XHTML page</title>
</head>
<body>
  <xmlns:html xmlns:xhtml="http://www.w3.org/1999/xhtml">
    <xmlns:head>
      <xmlns:title>example XHTML page</xmlns:title>
    </xmlns:head>
    <xmlns:body>
      hello world;
    </xmlns:body>
  </xmlns:html>
  <br />
  <xmlns:books xmlns:xhtml="http://www.w3.org/1999/xhtml">
    <xmlns:one>aaa</xmlns:one>
    <xmlns:two>bbbb</xmlns:two>
  </xmlns:books>
</body>
</html>
